We propose to study normal color vision, and the nature of defects in color which occur in individuals with stationary hereditary color defects ahd those which occur in various retinal and choroidal disease states. We shall use psychophysical techniques to measure the color defects and relate these defects to normal color vision and to the various disease states. We shall use retinal densitometry to study cone visual pigment kinetics in color defective observers and will evaluate the feasibility of studying cone visual pigments kinetics in patients with acquired macular disorders. In addition to empirical studies, we develop models of normal and abnormal color vision. Our theoretical approach is based in the question: To what extent can established biological or physical phenomena explain the data of color vision: This approach is one which allows us to examine the plausibility of various hypotheses which are not subject to direct experimental evaluation.